Sigma SD14 Resolution: 14 MP? 4.6 MP?How does the SD14 stack up against high end cameras like the Canon
EOD 5D?

by Mike Chaney
03/16/2007

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Revisions:

03/17/07, 12:00am EDT: Added real
shot comparison
03/17/07, 02:00pm EDT: Revised resolution tests to include all primary colors
and updated text to coincide w/new tests!
03/21/07, 10:30am EDT: Added 20D resolution tests and a write up on where the
SD14 stands among other dSLR's.
04/18/07, 04:30pm EDT: Update regarding problems I've been having with
the SD14
04/21/07, 07:30pm EDT: Sigma replaced my SD14 and things are looking better07/07/07, 07:45pm EDT: My final take on the SD1407/11/07, 02:30pm EDT: One last set of photos to ponder

Background

This article has become a sort of diary for my own experience
with the SD14 and the fun I've had comparing it to my Canon 5D during the
spring/summer of 2007. I would encourage you to read the entire article as
there have been some bumps in the road for the SD14 along the way.
Fortunately, Sigma has stood by their product and in the end, has delivered a
fine tool for photographers in the SD14. I hope you enjoy the article
which started out as a purely technical article, and became a bit more over time
as I gained more experience with the SD14 in more than just a technical
perspective.

It's not often that I get excited enough about a new camera to
take a look at some technical aspect of the camera, but whenever there is a
fundamental change that could affect the future of digital photography, I like
to discover just what the impact is and how it could affect future products.
Being the owner of Digital Domain Inc. and the author of
Qimage and
Profile
Prism, I don't have the time to do in depth camera reviews, take sample
photographs, critique the camera body and controls, and so forth. What I
can do is delve into the heart of what makes a new camera stand out from the
pack. Since Sigma introduced the SD9 as the first prosumer full color
capture camera, I've been hoping that the full color capture technology would take
hold and we'd soon see the end of cameras using single color capture (Bayer
mosaic) sensors. The RGBG sensors used in nearly all dSLR's today can only
capture one of three primary colors at each pixel: red, green, or blue.
The Foveon sensor used in the Sigma SD9/SD10 of yesteryear and the newly released
SD14 can capture all three primary colors at each pixel site on the sensor.

While all other consumer/prosumer dSLR's capture only 1/3 of the
color information for each pixel when compared to the SD14, what does this
really mean as far as image quality? Is the SD14 really comparable to 14
megapixel cameras? How could it be when the SD14 produces a 4.6 megapixel
final image? Sigma markets the SD14 as a 14 "megapixel" camera because it
records 14 million pieces of information for each image. By comparison, a
standard 14 MP dSLR also records 14 million pieces of information but it spreads
the color information thin in order to gain resolution. Few people can in
their own mind equate this to overall image quality to know what effect "full
color capture" has on actual photos.

The "Bayer Blur"

Having spent years developing color interpolation algorithms
that try to take one color per pixel and reconstruct the missing 2/3 of the
information, I can tell you I have never been a big fan of the Bayer RGBG sensor
design. In my opinion, it's simply a bad idea that has been implemented
with enough finesse to make it quite effective given the obvious limitations.
It's similar to the internal combustion engine which is also a very dated and
relatively simple
design that has been refined to the point that it actually works quite well.
Capturing one color per
pixel has inherent problems such as the fact that an antialiasing (basically
blurring) filter must be used to spread light over a larger (than one pixel)
area because at any pixel on the sensor, it takes a minimum of 9 pixels to
capture all three primary colors! The fact that so many (adjacent) pixels
are needed in order to estimate the color of any given pixel in the final image also means
that edge detail and sharpness can suffer significantly when shooting subjects
that only stimulate one or two of the primary colors. A deep red or blue
subject suffers the most since the red and blue sensors only account for 1/4 of
the pixels on the sensor. A red rose, for example, may be noticeably less
sharp and the veins in the petals may be far less detailed on a standard dSLR
because only the red pixels on the sensor are gathering any useful data.
At that point, your 12.7 megapixel Canon 5D has just turned into a 3.2 MP
camera. Fortunately, there are very few subjects that are the exact shade
of red needed to only stimulate the red pixels on the sensor. Even a red
rose will likely excite the green and/or blue sensors to some extent and even a
little bit helps as that information (in the blue/green sensors) can still be
used to resolve detail. Still, with the standard Bayer one-color-per-pixel
design, resolving power will drop off at least to
some degree whenever you are shooting a subject that is not black and white.
Both theoretically and in practice, a standard camera's resolving power will begin to drop whenever a
non-neutral color appears in the frame.

Bayer cameras and sharpness/detail variance

So what are the visual consequences of shooting with a camera
where the resolving power and sharpness vary depending on the color being
sampled? Basically, you end up with sharpness and detail inconsistencies.
You may shoot a red rose petal lying on a concrete walkway only to find that the
almost-gray concrete is tack sharp while the veins in the red flower petal
look mottled in comparison. Why? Because all pixels on the sensor
contain data for a gray object while only 1/4 of the pixels record significant
data for a red subject. The end result in layman's terms is that the photo
will look less "real" or will appear to have less "3D effect". I wrote
an article about this for Digital Outback Photo in 2004 and it was the
inspiration for the "sharpness equalizer" in
Qimage which can recover sharpness
based on reversing the detail inconsistencies with various colors on a Bayer
sensor. While it's a far cry from actually being able to recover data that
is lost due to the Bayer design, at least it does improve the 3D effect in Bayer
images by recovering a bit of sharpness for highly saturated colors.

A brief look at the SD14

The SD14 is the newest entry using Foveon's full color capture sensor design in a
Sigma camera. Full color capture means that all three colors (red, green,
and blue) are captured at each
pixel location on the sensor. Capturing full color eliminates the need for
the "Bayer Blur", antialiasing, and the "finagling" of color around edges that
can make some areas look unsharp on a standard camera. While the SD9/SD10
used similar technology, those cameras were more limiting in that they had no
in-camera JPEG shooting mode, a necessity for some journalistic type work, and color was often a bit inconsistent under
different lighting necessitating more color tweaking than would normally be
necessary. Still, the 3D effect or "presence" of images from the SD9/SD10
was unrivaled. Until now! The SD14 has improvements in color
accuracy, noise, and resolution that make it a solid contender that can compete
with the best dSLR's on the market today.

To be honest, I never quite got the hang of my Canon 5D. It
often underexposed even under relatively controlled conditions where my previous
300D, 10D, and 20D never had a problem, and I never quite got used to the full
frame light falloff that can darken the corners of some shots near the wide end
of the zoom range. Worse, I just could never get a shot from the 5D that I
felt lived up to my expectations as far as sharpness and detail. This
could be more a result of my lack of photographic skills than anything else
since I don't proclaim to be a professional photographer, but it's odd that I
never had trouble with my older 10D or 300D just as examples. To be honest, many of
my 5D photos actually look gorgeous printed up to 13x20 and even beyond, but
being on the software and engineering side of things, I'm a pixel peeper and I
often expect to see excellent detail when viewing the image on screen at 1:1
(100% zoom) and it just wasn't there. Sure, the 5D has so many pixels that
the amount of detail at 1:1 viewing on screen is of little consequence when
printing, but it
just might be a hint that all those extra pixels aren't quite adding up to what
they should mathematically and that's why I'm so excited about what I'm seeing
from the SD14 so far.

While I haven't taken enough shots with the SD14 to know if the
color consistency problems that I had with the SD10 have been solved and if the
camera does exactly what I need it to, it sure is producing shots that I'm
personally much happier with right out of the box than the 5D has been able to
give me in over a year working with it! Again, I'm not trying to "put down" the 5D
because we all know that a photographer must pick his/her tools and without a doubt
the 5D would be a better fit than the SD14 for others who are reading this,
particularly if you happen to have a large investment in Canon lenses.
For me, just after taking my first few dozen shots, I'm getting photos from the
SD14 that are simply in a different league from (better than) what I was getting
from the 5D. Is that just me? Am I just too lame to use the 5D
properly. ;-) Maybe. Time will tell once the more
photographically inclined reviewers start doing their real reviews of the SD14.
For now, I'm beyond impressed with the SD14 and the few issues I've found with
its operation appear minor and should be fixable with firmware updates! There is a bug in the v1.00 firmware that causes the
"color space" selection of Adobe RGB to not stick as it should and the setting
reverts to sRGB once the camera is powered down and back up. Actually, it
only partly reverts because some indicators show Adobe RGB while others show sRGB so
you really don't know what to think if you want to set the color space to Adobe
RGB and keep it there. If you have firmware v1.00, I'd suggest choosing
sRGB in the menu and leaving it there, as there appear to be multiple bugs
related to choosing Adobe RGB. I'm sure a firmware fix could easily address that
problem and it only affects JPEG shooting and not raw anyway which is where I
spend most of my time. The jury is still out on battery life since after
fully charging the battery, I only got about 15 shots before the battery
indicator was at the half depleted mark on the display. From what I
understand from others, the indicator seems to drop to halfway sooner than it
should and I have shot another 30 or so shots since then with the indicator
still sitting on the halfway mark so the indicator itself may be a bit liberal
in its estimation of usage. One little oddity popped up when playing back
images on the LCD in that I got some strange flashing/banding on the display.
A power off/on fixed it and it was an LCD display issue only as the images were
fine. It'll be interesting to see if that little glitch will pop up again.
Other than these few things making me feel that firmware v1.00 might be a little
glitchy, when you see the photos that this camera takes, the little things just
don't matter any more!

Hit me with your first shot!

After charging the battery, the first thing I did was to pop up
the flash and fire off a shot. At this point, my intent was to do nothing
more than make sure the camera was working, that I could download and process the
files, etc. I turned 90 degrees to my left where Jake was sitting in the
window and fired off this shot which shot in raw (because
that's the camera's default) and I developed as-is with no tweaks/changes.
This was my first shot from the camera, and the WOW factor had already hit me
like a freight train! With this first shot, I had already gone beyond the
level of sharpness and detail I thought possible with a camera. I had been
struggling for so long to get a shot with decent detail and sharpness with the
5D and I take one with the SD14 that blows me away just by "accident". From there,
things just got better and better! Since I've always had to "fight" my 5D
to get the proper exposure without tweaking the photos after the fact, I thought
maybe my first shot was just a fluke. My second shot,
however, had perfect exposure too, as have all 40-50 shots so far!

Resolution/detail: comparing the SD14 with the big boys

Revised 03/17/07: I have revised the resolution shots
to include six primary colors (red, green, blue, yellow, magenta, and cyan).
Red seems to be the worst case scenario for Bayer sensors so I wanted to get a
more balanced measurement using various colors. As a result, much of this
page from here forward has been revised.

Added 03/21/07: Added 20D resolution tests.

My findings with respect to the SD14's resolving power are about what I
expected. Visually, the detail and 3D presence of SD14 photos are amazing,
but I wanted to see if I could quantify this a bit. I already knew that as
far as resolving power, the 5D would have the edge for black and white detail
like that of a resolution chart, but what about the details in colorful
subjects? Would things start to fall apart when photographing subjects
close to primary colors like red or blue? Instead of looking at horizontal
and vertical lines on a typical resolution chart, I chose to use star
sector charts as they should be better suited for identifying the point at which both the 5D and SD14 are no
longer able to resolve detail reliably. The charts below all start at 500 LPI (lines per inch) at the outer most point where the lines are the thickest.
By measuring the distance from the outer edge to the point at which the lines
start to blur together, we can calculate maximum resolution. While I
confirmed that, as expected, the SD14 was able to resolve the same amount of
detail regardless of color, Bayer cameras like the 5D will have more or less
resolving power depending on the color being sampled.

Here are the resolution crops just as they came out of the cameras with no
resizing or tweaks other than a click on white to fine tune white balance. If you are wondering about
the reds, the SD14 appeared a bit weak on the reds while the 5D had a little too
much punch in the reds. The actual red was somewhere between the two. Neither camera was perfect with
respect to color accuracy under my mixed lighting but it was of little consequence for
this test. Images from the 5D are labeled "C" for "Canon" and images from
the SD14 are marked "S" for Sigma. Here, the SD14 images will obviously
appear smaller because the SD14 produced final photos that are about 4.6 megapixels compared to the 5D's 12.7 megapixels.

Notes on the setup:

Canon 5D using 24-70 f/2.8 L lens at mid zoom

Sigma SD14 using 18-50 f/2.8 lens at mid zoom

Both cameras set to f/5.6 aperture

Resolution chart framed the same way and covering the same area of the
image in both cameras

* Also tried Canon's DPP 2.0 for 5D and several other converters but Bibble
produced the best resolution.

Canon EOS 5D

Canon EOS 5D

Canon 20D

Canon 20D

Sigma SD14

Sigma SD14

Measured Resolution

Canon EOS 5D

Canon 20D

Sigma SD14

B/W

2100

1700

1700

Red

1630

1400

1700

Green

2000

1680

1700

Blue

1750

1480

1700

Yellow

1950

1600

1700

Magenta

1800

1500

1700

Cyan

2000

1700

1700

Average

1890

1580

1700

The resolution values listed above represent the point at which the lines
begin to blur/distort at any point around the arc of the circle. Imagine
placing the pin of a protractor at the center of the chart and drawing
concentric circles with the pencil starting at the outside edge of the chart and
moving in. As you move in, the first point where your pencil-circle meets
any lines in the graph that are blurred/smudged together, stop and the
resolution can be measured at that point. Of course, since these are
photos, we do this by using a photo editor and drawing circles digitally to see
where the blurring/smudging starts. Since there are some heavy handed
interpolation algorithms involved in reconstructing full color images from Bayer
cameras like the 5D, it's a good idea to look at the resolving power at many
angles and not just the horizontal, vertical, and 45 degree angles you see in
the typical ISO-12223 resolution charts posted on digital camera review sites.

As expected, the 5D takes the lead on resolving power for B/W, but it also
steps ahead on green, yellow, and cyan detail. The 5D's lead starts at
about 24% for B/W detail but that advantage drops to about 18% when capturing
green, yellow, and cyan colors. Due to the lack of a green component, the
5D's lead drops to only a 6% advantage for magenta, less than a 3% advantage for
blue, and actually falls behind to a 4% deficit when capturing red colors
which seem to be the worst case scenario for Bayer sensors. Why?
While red and blue sensors are spaced identically on the sensor and one would
expect the same resolving power for red and blue, blues fair a bit better simply
because they often carry a weak green component, meaning that it is easier to
find reds with no green component than blues with no green component.

While on average, the 5D does seem to have a 10% to 15% advantage in
resolving power, by the numbers (megapixels in the final images), you'd expect a
65% advantage in all directions. The use of antialiasing filters and the
complex color reconstruction algorithms are the primary reason that the 5D
cannot realize the full 65% advantage. It is also important to note that
while in some cases, the 5D pulled better max resolution than the SD14, the
detail at that cutoff point was often very soft due to the amount of
interpolation going on. In contrast, the SD14 was able to carry sharp
detail all the way to its max resolving power, however, as a result of the lack
of "smoothing" being done, the SD14's tradeoff was an increase in aliasing at or
beyond max resolution. A tradeoff for sure. The worst part of the
test for the 5D is that with resolving power varying by as much as 25% for some
colors, the eye can pick up on the fact that some detail in the photo just isn't
as sharp as it should be when the photo consists of subjects with widely varying
color. The SD14's consistent resolving power give photos a more 3D
appearance. It is important to preserve the relationship between detail,
sharpness, and depth-of-field throughout the photograph and this is where Bayer
cameras fall behind by not being able to reproduce the same realism as a full
capture sensor under many shooting conditions. This effect is quite
noticeable on the tests above as well as in real shots. If you look at the
RGB chart for the 5D versus the SD14, the 5D makes the red and blue swatches
look as if they are disconnected from (either in front or behind) the rest of
the chart due to the obvious inconsistency in sharpness. The SD14 shows
consistent sharpness all the way around as it should, and you can tell that all
colors are on the same piece of paper.

Added (3/21/07): So where does
the SD14 rank among other dSLR's as far as resolution?

The 8 megapixel 20D is unable to resolve as much overall detail as the SD14.
Though they both resolve about the same amount of detail for B/W and green
colors, the SD14 takes the lead for all other colors tested.
From the data, we can infer that the overall resolving power of the SD14 lies
somewhere between the 20D and the 5D: that is, somewhere between 8 megapixels
and 12.7 megapixels. For overall resolving power, the SD14 appears to
compare to a typical (Bayer) 10 MP dSLR. Keep in mind here that my
findings that a Bayer based 10 MP dSLR resolves about 1700 LPI overall will be
lower than the resolution measured by other review sites that only consider
horizontal, vertical, and 45 degree detail from a single B/W chart because I
consider lines at many different angles and a range of colors other than just
B/W. Saying that the SD14 is approximately equivalent to a 10 MP Bayer
dSLR, however, is a bit like comparing apples and oranges. A typical 10 MP
dSLR may be able resolve detail as small as 1700 lines per inch, it does so a
bit differently than the SD14.

When I state that both the SD14 and a standard 10 MP dSLR can resolve about
1700 lines per inch, I must qualify that statement. To my eyes, the SD14
produces better photos than a typical 10 MP dSLR because it is able to carry
sharp detail all the way to the "falloff" point at 1700 LPI whereas contrast,
color detail, and sharpness begin to degrade long before the 1700 LPI limit on a
Bayer based 10 MP dSLR. Any Bayer dSLR will begin to lose significant
chroma (color) information when different colors are being captured near the
resolution limit. For example, tiny red spots on a white flower will begin
to lose saturation as the dots become small enough to approach the resolution
limits of the Bayer camera. In fact, the red dots will begin to start
losing saturation as far back as 1000 LPI on the 10 MP Bayer camera while the
SD14 will show a more accurate/vibrant red much further toward the 1700 LPI
resolution limit.

As a consequence of the varying levels of sharpness, contrast, and color
across different hues and spatial frequencies, many SD14 images look sharper and
appear to have more 3D effect or "presence" when compared to Bayer based 10 MP
photos. A necessary evil, however, to the fact that the SD14 can resolve
pixel level detail is the fact that aliasing can appear more prevalent in SD14
photos, especially when you look at detail at or beyond its 1700 LPI resolution
limit. To the observer, this can make SD14 photos appear jaggy in some
areas and areas of repeating fine detail at or near the 1700 LPI limit can
suffer from moiré. In some cases where
repeating fine detail is being recorded, the 10 MP Bayer camera may actually
produce less "distracting" photos as they tend to smooth over these artifacts.
Unfortunately, they also smooth over some detail as well so as stated
previously, the fight to balance aliasing and resolving power is a tradeoff.
I tend to prefer the pixel level detail of the SD14 over the antialiasing
methods of a standard dSLR however, because aliasing can be corrected via a
number of blurring algorithms for photos where this is an issue, but once the
data is "blurred" up front, there is no way to get the detail back.

The bottom line in the debate about where to place the SD14 among other
(Bayer based) cameras is that I believe the SD14 to be about equivalent to a 10
MP Bayer dSLR as far as pure (maximum) resolution. When taking into
account how the camera achieves that resolution, however, I would have to say
for image quality, the SD14 compares well to standard dSLR's a little closer to
12 MP, that is, more comparable to something like the Canon 5D. When
taking equivalent shots of "real" subjects and examining SD14 and 5D photos side
by side, SD14 photos compare nicely to photos from the 5D. I've done a
number of these tests and in scrolling around with my "pixel peeping" hat on, I
can always find some areas that I like better on the SD14 and other areas that I
like better from the 5D photos. For image quality alone, it's a toss-up
for me when comparing the SD14 and 5D. The SD14 seems to have a little
less consistent/controllable color than the 5D but the SD14 produces that 3D
presence that no other standard dSLR can match. In the race to get the
best image quality, I suspect some will like 5D photos better than SD14 photos
and vice versa. The mere fact that the SD14 compares so well to cameras
like the 5D is a testament to how good the SD14 really is!

Since words like "data", "quality" and "resolution" can become
intertwined, it is sometimes beneficial to take a look at the images at the same
size. What would the SD14 images look like if they were upsampled
(interpolated) to the same size as the 5D photos? At first glance, this
may seem like "cheating" but consider the following and you may realize how
valid the comparison really is!
Since the 5D is already interpolating (read guessing) two thirds of the color information in it's
photos, why not interpolate some of the resolution information in the SD14 for
comparison since it starts out with nothing being interpolated? Here's what the SD14 charts look like when interpolated to the
pixel count of the 5D using a good interpolation algorithm (I used the "Hybrid"
method in
Qimage).

The above images are animated and should switch back and forth
between Sigma SD14 (S) and Canon 5D (C). You can see how the 5D has the
edge in some areas but not others. The 5D boasts final image resolution of 4368 x 2912
while the SD14 offers a final resolution of 2640 x 1760 which equates to 12.7 MP
for the 5D and 4.6 MP for the SD14. When comparing final image sizes, the
5D has 65% more pixels in both directions (horizontal and vertical), however, it
isn't surprising that the 5D can't capitalize on more than a fraction of that
65% in reality and falls short on detail for saturated colors. My findings
that the 5D slips ahead of the SD14 on B/W resolution while falling
behind (either via resolution or sharpness) in some saturated colors is expected, really.
The color interpolation algorithms used to reconstruct a full color image from a
single-color-per-pixel photograph are quite complex and between antialiasing
filters and the logic needed to guess two thirds of the information at each
pixel, there is understandably some resolution loss in the process before the 5D
spits out that final photo. I believe that the star sector resolution test
is a much more accurate method of determining real world resolution since in
real photographs, we have more than just horizontal and vertical lines.
Determining resolution by looking at a B/W chart with mostly horizontal and
vertical lines is really of little merit when comparing different technologies
such as Bayer versus full color capture because it does not adequately expose
the weaknesses of the Bayer design and those are weaknesses that definitely show
up in real photographs.

Revised (3/17/07): What about "real photos"

Wouldn't it be nice if the inconsistencies in resolving power of
the Bayer sensor design were limited to only red and black mathematically
derived resolution targets! One of the first criticisms to any scientific
test seems to be, "but that problem will never appear in real photos".
Sadly, this is not the case for the Bayer sensor as the issues of edge blurring
and inconsistent resolving power across subjects of varied color are present in
many "natural" shots that contain saturated colors. The issue is
particularly noticeable in bright colored flowers and also fabrics where texture
such as thread weave brings the inevitable blurring of the Bayer sensor design
to the surface. In real shots, I'm finding upsampled SD14 photos to be
every bit as detailed as the 5D across the board and better for certain problem
colors like deep reds and blues. Below are some 1:1 crops from a shot of
the same flowers taken in raw mode on both cameras and developed without any
tweaking of the images:

On the surface, it may seem unlikely that a 4.6 megapixel image
upsampled to 12.7 MP can look as good or better than one that started as 12.7 MP
but the proof is in the shooting! Even though the SD14 photo on the right
above started as a much smaller image, when upsampled to match the resolution of
the 5D, it holds up very well, easily matching the 5D in most areas while
surpassing it in others. Where the SD14 holds consistent sharpness across
the frame, the 5D has smudged over a bit of detail in areas notoriously
problematic for Bayer sensors such as the red carnation and even the white
flower where edge detail is being lost to the AA filter. Looking at the 5D
shot, you'd be tempted to believe that the red flower is just a little out of
focus because it's in front of (or behind) the other flower due to it not
looking as sharp. In reality, all the flowers in the above crop are in the
same plane relative to the lens. In addition, the shot was taken from a
distance at f/11 so much of the depth of field is quite forgiving as well.

To be fair, the 5D did a little better overall with respect to
color accuracy as the true purple tones of the flowers at the top/middle show
more accurately in the 5D shot. The reds are actually somewhere between
those depicted in the 5D shot and the SD14 shot as neither got the reds the
perfect shade. Since I used Bibble 4.9 to process the 5D shots versus
Sigma Photo Pro 3.0 for the SD14, I suspect much of the difference in color
accuracy is due to the raw converter being used. I look forward to more
raw conversion tools eventually supporting the SD14 in a truly color managed
workflow.

Bottom Line

The bottom line here is that the SD14 appears to compare
favorably to high end cameras having final images with significantly higher
pixel counts. Is the SD14 equivalent to a standard 14 MP camera? As
you can see from the above, that would depend on the circumstances and what you
are shooting. I've upsampled a number of SD14 shots to 5D resolution and
in most areas of near gray or only lightly saturated colors, there is actually
very little visible difference between the SD14 and 5D shots as far as detail or
resolving power. Throw in some saturated colors, however, and the detail
and 3D appearance of the SD14 might just edge out the 5D! The consistency of sharpness and detail
throughout the entire photo, no matter what color your subject, cannot be
explained without being seen on the SD14. To some, the Canon name might be more
important than the Foveon/Sigma innovation but I think the
SD14 web site asks a
relevant question with respect to brand loyalty by pointing out that technology
that is fundamentally better may be worth more than an extra feature or two, or
a metal body that can survive a 10 foot drop to concrete. At least until
you drop your camera from 10 feet onto concrete. ;-) Different
people will always have different needs and that's why there are so many cameras
out there. So far, it looks like the SD14 lined up at the starting line
and may well be jumping ahead of the rest of the pack at least as far as image
quality. From what I can see by my initial look at this camera, image
quality has pushed the SD14 ahead of competitors costing twice as much.
Whether it can stay in front will depend on many factors not the least of which
are reliability, usability from a real photographer's standpoint, and how it is
received by the public. Speaking of public perception, one of my reasons
for doing this article is to point out to potential buyers that the SD14 really
is fundamentally better technology. Even though it's final images are 4.6
MP, it really is comparable to standard cameras that deliver final images 2-3
times larger in final resolution. For those who would be tempted to look
at those 4368 x 2912 5D photos, comparing them to the 2640 x 1760 SD14 photos
and say, "But what if I want to print a 24 x 36 inch print", don't be fooled by
the Bayer resolution myth! The SD14 looks at a scene and records 14
million pieces of information in a balanced manner, sampling both color and
resolution at the highest quality. Other ~14 MP cameras record the same
amount of data, but give you a false sense of security by "stealing" two thirds
of the color information from each pixel and attempting to use it for
"resolution". Make no mistake, whether you want to call the SD14 a 4.6 MP
camera or a 14 MP camera, it's in the running with the best on the market today
and in my own personal opinion, beats most of them for total image quality!

Update (4/18/07): My SD14
develops major problems!

The above testing was done mostly in the confines of my small
office and most shots were taken from a distance of about 6 ft to 8 ft.
The SD14 focused normally in that range but once I started shooting macros and
telephoto shots I noticed that I kept getting out-of-focus shots. After
much testing, I found that the camera focuses in front of the subject in macro
mode and well behind the subject when shooting a subject at the telephoto end of
the lens (18-50 f/2.8 lens) when the subject is more than about 10 feet from the
camera. This is repeatable time after time with only the center focus
point being used. The camera only focuses properly when the subject is
between about 4 and 8 feet from the lens and my other lens (15-30) behaves
identically so I know it is the camera and not the lens. With firmware
1.00, I was also experiencing major problems with lockups, reboots, failure of
the shutter to release, etc. so I sent the camera back outlining both problems
in detail. I was surprised that I had to send the camera in and pay for
the shipping (to Sigma service) myself when both Nikon and Canon have provided
prepaid UPS boxes for the same service in the past but I just shrugged my
shoulders and sent the camera to NY for service. Unfortunately after 10
days, I received the same camera back from Sigma with nothing but new firmware
(focus issue not addressed) so I now need to ship the camera back to Sigma again
and await a replacement. Hopefully the replacement will do better as I'm
beginning to wonder if the Sigma body/firmware are worthy of the Foveon sensor.
I'll be sure to update this page once I have the replacement camera.

Update (4/21/07): My replacement
SD14

After the initial mixup where Sigma service sent my defective
SD14 back to me, they turned it around very quickly the second time around and
sent me a replacement. The new SD14 is working much better than the old
one as far as focus is concerned. The new SD14 came loaded with v1.01
firmware yet it still has an occasional lockup that can sometimes even interrupt
shooting. In addition, firmware 1.01 only fixes one of the three problems
associated with shooting Adobe RGB JPEG's so JPEG shooting with Adobe RGB is
still unreliable at best. The new camera with 1.01 firmware only locks up
occasionally such as when shooting buffered shots quickly so it is certainly not
as bad as the initial 1.00 firmware. Sigma appears to be going in the
right direction. I'm hoping firmware v1.02 will cure the few remaining
lockup problems and the remaining issues with Adobe RGB color space when
shooting JPEG's.

Update (7/07/07):
My final take

The last few months have given me more time to appreciate the
SD14. Firmware v1.03 has cleared up all remaining issues I had with the
camera and I find that it is becoming more and more my tool of choice for all
around shooting. I've used both the Canon 5D and Sigma SD14 for the last
four months, trying to give ample hands-on time to both cameras. They are
both excellent cameras so I find myself sometimes preferring the Canon and
sometimes preferring the Sigma. When the Sigma runs out of buffer and is
slow to take the next shot, hunts a bit for AF, or occasionally gets a horrid
auto WB, I find myself saying "The Canon wouldn't do that". Other days, I
struggle to get a photo from the 5D to be as sharp as the SD14 without adding
too much noise, or I come across another example of the "Bayer Blur" (below)
where color detail gets smudged on the Canon and find myself saying, "The Sigma
wouldn't do that". In the end, I tend to err on the side of image quality
where I do think the SD14 has a slight edge under some conditions, and the
result is less surprises like the one below.

The example below shows how I was recently shooting some Bottle
Brush blooms with the 5D and the 5D literally ruined the shot making the
bristles on the flower very jagged due to the tendency of Bayer cameras to lose
significant resolution for certain primary colors. The word "ruined" may
seem a bit extreme in this case, but my intention was to do a large print and
the 5D let me down right where I needed the most detail in the shot: and it
would certainly show on just about any print beyond 8x10. I reshot it
several times with the 5D and each shot showed the same artifacts. I then
shot it with the SD14 and got a beautiful shot the first time around. I
show the example below only as a curiosity since the photos aren't cropped
exactly the same nor did I do any color correcting (which I find the Sigma needs
more often than the 5D), but the idea comes across. The shots below are
raw conversions with default values and they stayed in TIFF format until saved
for the web. I used ACR 4.1 for the 5D and Sigma Photo Pro 3.0 for the
SD14. I did try Bibble and RSP for the 5D but the artifacts were just as
bad on the 5D regardless of the raw tool used. As to the closeup of the
green leaf, I could certainly have brought out more detail from the 5D shot
using some extra sharpening, but I find doing that really brings out background
noise in the 5D shots. The worst effect, of course, is seen in the
bristles on the 5D shot where the 1/4 resolution red sensors just didn't have
enough data to determine which way the lines were really going! You may be
tempted to think that this is a once in a lifetime occurrence, but it happens
quite often when shooting things like red flowers and blue fabric. Others
have reported a blurring of the blue channel on the SD14 for red and yellow
colors, but I haven't seen any such problem on my own shots up to ISO 800 (I
rarely go beyond ISO 800). I've actually found the 5D to be noisier than
the SD14 and the 5D is pretty clean although I have had some banding noise
issues with the 5D!

I took a second more controlled shot (below) where I made sure
to sharpen the 5D shot just enough to match the sharpness of the SD14.
Intentionally trying to reduce artifacts on the 5D, I also made sure that the
leaves under the blossom were in the same focal plane and I shifted the camera
position so that no blue (sky) is showing behind the blossom as red on blue is
the most difficult combination to render with good detail on a Bayer camera.
As before, camera settings on both cameras were identical: ISO 100, 50mm, f/6.3,
1/200 shutter, and manual WB on WhiBal card. The only difference in the
shot was that I had to move the 5D a bit closer to the flower in order to frame
the shot the same since the SD14 has a 1.7x crop. This time, the 5D fairs
a bit better on the green leaf below the blossom but the same stair-stepping
artifacts are present in the bristles of the red flower in the 5D shot.
The problem is not quite as pronounced with a red-on-green shot as it was above,
but the jagged edges are still quite noticeable just viewing at 100% (no zoom).
Also, take a look at the 200% zoom of the background from the same shot.
The 5D shows significantly more visible noise.

Noise profile from the same shot:

5D 200% zoom

SD14 200% zoom

Update (7/11/07):
One last set of photos to ponder

Canon 5D 100% crop

Sigma SD14 100% crop

Full JPEG conversions of the above raw photos can be downloaded
below so that the entire image can be examined. The focus point on both
cameras was the middle of the crop above. This photo has been framed
identically in both cameras and shows a receding fabric below the flower so that
depth of field can be examined. Be your own judge. Personally, there
are certain aspects of this photo that I think were dealt with better by the
SD14 such as overall red resolution and other aspects where I feel the 5D had an
advantage such as better/smoother separation of the RGB color channels.
The phenomenon of smoothed-over detail in the blue and green channels on the
SD14 can be seen in this photo. The more tests I do, the more I'm
convinced that this smudging of the blue and sometimes green channel on red
objects is caused not by noise reduction or smoothing, but rather by a
propensity for the Foveon color separating algorithms to clip the blue/green
channels at a certain point when rendering specific shades of red. Also
worthy of note is that the 5D recorded what appeared to be specular reflections
on parts of the flower petals making them appear almost oversharpened (and the
photo was only sharpened enough to match the sharpness of the SD14 shot).
Those specular reflections were not observed on the flower in person even when
viewing under a 10x loupe. Here, it appears that the color separating
process of the SD14 made the petals seem a little too velvety smooth while the
5D did the opposite, creating some extra frosting on the leaves. The real
flower actually looked like a compromise between the two. Note that to
minimize motion blur, both cameras were on a sturdy tripod and the shot was
taken indoors using sunlight through a window.

Less surprises caused by inconsistent resolving power for
different colors

Very accurate color IF you take the time to get a good WB

Very low noise under most shooting conditions

Final photos are smaller in size (easier to work with/transfer)
yet contain more real data than cameras boasting 2x the final resolution

Cons:

Slow buffering may impede quick shooters

AF a little pickier than most: takes more practice to get good
focus on the first try

Battery life not phenomenal

Auto WB sometimes way off, although easily fixed if shooting raw

Certain colors have a slight hue shift, particularly red and
purple: hopefully SPP software can improve this in the future

That's about it for the major points. There are just as
many cons as pros above, but I tend to put a lot of weight on final image
quality where the SD14 really stands alone in today's camera market. Sure,
there are other cameras that do just as well or better for your average photo,
but in the end, the competitors sometimes fall flat when it comes to capturing
fine color detail like that shown above. I have yet to see another
reviewer really test this (properly). As a result, many reviewers tag the
SD14 as more hype than hero as they tend to focus on B/W resolution charts or
when they do test color detail, they make mistakes like not matching the lenses
properly or using proper test patterns that really show the problems with Bayer
cameras. I'm certainly not one who puts the SD14 in the hype category!
To me, someone who knows the compromises made when sampling only one color per
pixel, I can only hope the SD14 is one of many full color capture cameras to
come! Not only do the benefits of full color capture show up in lab tests,
they show up in the real world too. Who knows, maybe part of it is
psychological. Now that I've shot with the SD14 and I've seen how the
Bayer design can let you down, I'm aware of it and I know it can rear its ugly
head at any time. ;-) I guess I just like knowing that the quality
of my photos won't be driven by the color(s) of my subject. For that, I
give the SD14 top honors as there really is nothing else in the running!

Other articles

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